Yep, the 7-year itch is real! Happened every 7 years between me and my ex. Don't believe that the itch is all about wanting to sleep with others. It's about needing to emotionally reconnect, find that non-sexual intimacy again that you shared when things were new. On the 3rd round (just under 21 years) we called it quits. However, that was due to many things. We were pretty good at re-connecting up until the last time (he confessed to having cheated, so....well... it wasn't worth it to me anymore, I had no more trust!).
Anyway, how we successfully did it before? Through letters/notes/emails. Why not just say it verbally? I had a man who would emotionally shut down when things got tough when we'd talk face to face about our needs. He would just turn off! I wrote him a letter the first time and it worked! We did it ever since. That way, we could say it without interruption, without emotionally freaking out, whatever. Then talk about the letters and come up with plans to rectify the issues.
What to put in the letters/notes/emails? Needs, wants, desires. Nothing should be stated accusatory, like, "You SAID you were gonna do X, but I'm still not feeling it!" Instead try something more like, "I really miss when we..." or, "I love you so much, and I would really appreciate it if WE..." Using the term, "YOU," can make people get very defensive, "You didn't; you could have; I wish you." Instead use, "I wish we" or "We should try," which makes the reader feel that you are also sharing responsibility in whatever's going on and not just dropping it at their feet.
State your plan to correct you side and state that you would love to hear their opinions/suggestions as well.
Always end it on a positive note, like, "you are the love of my life. This trouble is only short-term. I know we can do it together." cheesy, but you get the idea!